Network-based computing[1-5,10] has been considered as an economical alternative to supercomputing. In network-based computing, workstations connected by a general-purpose network function as a large-scale distributed system and provide a transparent interface to the user. However, traditional design of computer architecture did not consider the communication requirement as the first priority. Communication between workstations involves excess software/hardware overhead. The introduction of high-speed networks such as ATM dramatically increases the network bandwidth but the software/hardware overhead incurred on the network interface is not reduced. Without architectural support, network-based computing is only applicable to coarse grain applications.
II. Goal and Approach
It is crucial to identify and solve the communication bottlenecks to make network-based computing more useful. Our previous studies, with experiments on a network of workstations, have identified the bottlenecks and we have proposed a new communication architecture, including network interface design, low-level messaging layer and a set of application programming interface(API), to solve these problem.
Since architectural changes are expensive and time-consuming, simulation is adopted to verify our communication architecture. We chose PAINT as the base simulator and implemented our proposed communication architecture on it. Microbenchmarks and macrobenchmarks are used to measure the performance. Microbenchmarks include simple applications to test the end-to-end communication latency and deliverable bandwidth. Macrobenchmarks contain a set of scientific applications, e.g. Numerical Aerodynamic Simulation suites, to demonstrate the performance for parallel processing.
We have derived preliminary performance numbers for point-to-point communication and collective communication . The following figure shows the application level one-way latency between two nodes. Our result is compared with two other fast messaging softwares: MPI-GAM and MPI-FM, which are MPI implementations based on Generic Active Messages and Fast Messages respectively.
Our simulation for microbenchmarks has shown better performance than other fast messaging softwares. Currently, we are implementing some macro-benchmark applications and will use them to further demonstrate the advantages of our communication architecture.
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